#include <iostream>

class WaterMeter
{
private:
	double flow;
	double price;
public:
	WaterMeter(double f, double p)
	{
		flow = f;
		price = p;
	}

	void calculater()
	{
		money += flow * price;
	}

	static double money;
};

double WaterMeter::money = 0.0;

int main()
{
	WaterMeter A(3.9, 2.8);
	WaterMeter B(134.5,4.1);
	A.calculater();
	B.calculater();
	std::cout << B.money << std::endl;


	return 0;
}

